1. Field of the Invention
This invention relates in general to wheel hub lubrication systems and, in particular, to an improved oil-bath wheel hub lubrication system that eliminates the necessity of an air vent to relieve excess internal pressure.
More specifically, but without restriction to the particular embodiment and/or use which is shown and described herein for purposes of illustration, this invention relates to an improved oil-bath wheel hub lubricating system that utilizes a heat sink incorporated into the structure of the lubricating system closure cap to dissipate heat build-up which occurs due to hard braking or extended travel over hot roadways.
2. Description of Related Art
As is known to those skilled in the art, trailer wheel and axle assemblies rotatably mount a vehicle wheel hub on a wheel spindle which is in turn supported by an axle connected to the trailer by springs. The wheel hub defines a cavity for containing a lubricant, grease or oil, to lubricate bearings carried by the wheel spindle, and upon which the wheel hub is mounted for rotational movement. While in all such wheel mountings it is preferable to keep moisture out of the wheel mounting structure, in the mounting of wheels on boat trailers the problems associated with moisture entering the mounting structure is exacerbated because of the frequency with which the trailer wheels are immersed in or submerged under water. Water, especially salt water, and other contaminants entering into the wheel hub lubrication cavity can quickly cause the wheel bearings to fail.
When boat trailer wheels are submerged in water shortly after extended travel over a roadway, or after continuous braking, the internal pressure within the sealed wheel hub mounting structure which increases because of heat build-up is suddenly decreased when the wheel hub is immersed in or submerged under water, thereby creating a negative pressure in the lubrication cavity which could draw water into the wheel mounting structure if the inner seal is not sealing correctly. The presence of water within this structure degrades the effectiveness of the lubricant, and can cause the internal components thereof to rust. Accordingly, many wheel hub mounting structures have been developed in an attempt to solve this problem.
One attempt to solve this problem is through the use of an oil-bath wheel spindle and hub assembly that has an open vent to the atmosphere to prevent internal pressure build-up, but which prevents water from entering into the interior of the wheel hub. Such a wheel hub and spindle assembly is disclosed in L. N. Johnson, U.S. Pat. No. 5,098,168, wherein there is disclosed a waterproof hub and spindle assembly having an air chamber open on the bottom and adapted to trap air therein as the hub and spindle assembly is submerged. The air in the chamber is compressed as submersion increases which pressurizes the lubricating chamber to prevent contaminants, such as water, from entering into the bearing structure. Another attempt to solve this problem is disclosed in D. B. Law, U.S. Pat. No. 3,077,948, wherein an excess supply of lubricant, such as wheel bearing grease, is maintained in an attachment to the wheel hub, and the grease supply is pressurized so that a supply of grease will be available for lubricating purposes so long as an adequate supply of grease is maintained in the attachment, and the appropriate pressure is applied with a grease gun just before launching.
While these and other such attempts have met with some success, the present invention addresses this problem by utilizing a structure which functions to dissipate heat build-up in the wheel hub, to thereby minimize or eliminate any internal pressure increase within the wheel hub due to heat build-up.
It is an object of this invention to improve wheel spindle and hub assemblies.
It is another object of this invention to improve wheel spindle and hub assemblies used on trailers by dissipating heat build-up in the wheel hub and spindle assembly to minimize or eliminate pressure increase within the lubricant containing cavity.
A further object of this invention is to maintain the integrity of the wheel spindle and hub seals of a trailer by preventing excessive heat build-up when the trailer is moving over a roadway or the trailer brakes are being applied.
Yet another object of this invention is to prevent a reduced pressure from being created within the lubricant containing cavity of a wheel spindle and hub assembly when a boat trailer is immersed water.
These and other objects are attained in accordance with the present invention wherein there is provided an oil-bath wheel spindle and hub assembly having a heat dissipating oil seal cap forming a heat sink to transfer heat away from the wheel spindle and hub assembly to ambient atmosphere.